As a filter medium for reducing dust entering vehicles, a fiber-based pocket-type or cassette-type product is used in most cases. However, there is a problem that such fiber-based pocket-type or cassette-type product causes an energy consumption increase in a vehicle duct system to increase dust collection efficiency. A duct system can consume up to 38% of the energy produced by a vehicle battery. Accordingly, a key issue is to reduce the energy consumption of a duct system in future electric vehicles.
To effectively reduce dust, harmful microorganisms, and toxic gases, a multistage system characterized by including an independent filter medium for each object to be removed has been used along with a method of further refining the size of a filter medium to improve the removal efficiency of fine dust. However, both methods caused an increased pressure drop. In addition, since a manufacturing process thereof is based on a liquid chemical process, functional materials are present inside fiber, not on a surface of the fiber, and, accordingly, there is a limitation in utilizing functional materials.
With regard to this, Korean Patent Application Publication No. 2014-0103866 discloses a filter medium and a method of manufacturing the same, but does not propose a counterplan regarding the problems.